In recent years there has been in increased demand for further miniaturization of electronics, machines, and optics. By example, the development of integrated optics, diffractive optics, waveguides and, more recently, capillary electrophoresis chips for faster DNA sequencing, all require improved, faster, and more flexible methods for manufacturing small (e.g., micron-scale) devices. One of the more commonly used media for patterning in microelectronic, optoelectronic, and micromachine applications is silicon dioxide. Currently, photolithographic techniques are used primarily to pattern silicon dioxide. One major drawback to photolithography is the numerous steps that are necessary to pattern the surface. For example, direct exposure of lithium dioxide/silicon dioxide glasses to 245-nm light and subsequent baking procedures are required for local devitrification. The exposed areas can then be selectively etched, permitting the production of features of the order of several tens of micrometers. Direct exposure of glass to high-energy ion beams and electron beams has also been shown to lead to an increased etching rate in the exposed area and has been proposed as a potential patterning technique.
One way of circumventing some of the required steps of photolithography is to use photo-sensitive glasses, such as one known as Foturan.TM. that is available from Schott Corporation, Yonkers, N.Y. This is an alkali-aluminosilicate based glass that is doped with metallic ions (silver), and which is sensitive to wavelengths between 280-340 nm (UV). The material is irradiated with UV, then baked, and then etched. During baking the metal ions nucleate within the irradiated regions. During the subsequent etching process the portions of the material that contain the nucleated metal etches at a different rate than the remainder of the material.
While such glasses may improve the flexibility of patterning structures onto glass, they suffer from low resolution limitations, with minimum feature sizes of about 25 .mu.m and a surface roughness of 1 to 3 .mu.m. In addition, and although the number of steps required to produce the features are reduced as compared to photolithography, before etching the material requires baking at high temperatures (400-600.degree. C.) for a significant period of time (e.g., one hour).
In general, conventional techniques present several drawbacks, including a lack of resolution required to accurately delineate and fabricate micron-scale structures, and excessive process complexity and/or processing times.